kernel/arch/powerpc/include/asm/vas.h, branch linux-6.2.y

powerpc/powernv/vas: Assign real address to rx_fifo in vas_rx_win_attr

2022-05-22T05:58:27Z

In init_winctx_regs(), __pa() is called on winctx->rx_fifo and this function is called to initialize registers for receive and fault windows. But the real address is passed in winctx->rx_fifo for receive windows and the virtual address for fault windows which causes errors with DEBUG_VIRTUAL enabled. Fixes this issue by assigning only real address to rx_fifo in vas_rx_win_attr struct for both receive and fault windows. Reported-by: Michael Ellerman Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/338e958c7ab8f3b266fa794a1f80f99b9671829e.camel@linux.ibm.com

powerpc/pseries/vas: Modify reconfig open/close functions for migration

2022-03-07T13:04:56Z

VAS is a hardware engine stays on the chip. So when the partition migrates, all VAS windows on the source system have to be closed and reopen them on the destination after migration. The kernel has to consider both DLPAR CPU and migration events to take action on VAS windows. So using VAS_WIN_NO_CRED_CLOSE and VAS_WIN_MIGRATE_CLOSE status bits and windows will be reopened after migration only after both status bits are cleared. This patch make changes to the current reconfig_open/close_windows functions to support migration: - Set VAS_WIN_MIGRATE_CLOSE to the window status when closes and reopen windows with the same status during resume. - Continue to close all windows even if deallocate HCALL failed (should not happen) since no way to stop migration with the current LPM implementation. - If the DLPAR CPU event happens while migration is in progress, set VAS_WIN_NO_CRED_CLOSE to the window status. Close window happens with the first event (migration or DLPAR) and Reopen window happens only with the last event (migration or DLPAR). Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0aad580387cb58379496b4cbbd7c5596e9ea70be.camel@linux.ibm.com

powerpc/pseries/vas: Close windows with DLPAR core removal

2022-03-07T13:04:55Z

The hypervisor assigns vas credits (windows) for each LPAR based on the number of cores configured in that system. The OS is expected to release credits when cores are removed, and may allocate more when cores are added. So there is a possibility of using excessive credits (windows) in the LPAR and the hypervisor expects the system to close the excessive windows so that NX load can be equally distributed across all LPARs in the system. When the OS closes the excessive windows in the hypervisor, it sets the window status inactive and invalidates window virtual address mapping. The user space receives paste instruction failure if any NX requests are issued on the inactive window. Then the user space can use with the available open windows or retry NX requests until this window active again. This patch also adds the notifier for core removal/add to close windows in the hypervisor if the system lost credits (core removal) and reopen windows in the hypervisor when the previously lost credits are available. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/108928f9c00a48cc6a722315d482d07cf66acf5a.camel@linux.ibm.com

powerpc/vas: Add paste address mmap fault handler

2022-03-07T13:04:55Z

The user space opens VAS windows and issues NX requests by pasting CRB on the corresponding paste address mmap. When the system lost credits due to core removal, the kernel has to close the window in the hypervisor and make the window inactive by unmapping this paste address. Also the OS has to handle NX request page faults if the user space issue NX requests. This handler maps the new paste address with the same VMA when the window is active again (due to core add with DLPAR). Otherwise returns paste failure. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/3956e1c1fdfde69127055ff1c0256c7d71104030.camel@linux.ibm.com

powerpc/pseries/vas: Integrate API with open/close windows

2021-06-20T11:58:57Z

This patch adds VAS window allocatioa/close with the corresponding hcalls. Also changes to integrate with the existing user space VAS API and provide register/unregister functions to NX pseries driver. The driver register function is used to create the user space interface (/dev/crypto/nx-gzip) and unregister to remove this entry. The user space process opens this device node and makes an ioctl to allocate VAS window. The close interface is used to deallocate window. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e8d956bace3f182c4d2e66e343ff37cb0391d1fd.camel@linux.ibm.com

powerpc/pseries/vas: Define VAS/NXGZIP hcalls and structs

2021-06-20T11:58:56Z

This patch adds hcalls and other definitions. Also define structs that are used in VAS implementation on PowerVM. Signed-off-by: Haren Myneni Acked-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/b4b8c594c27ee4aa6be9dc6dc4ee7331571cbbe8.camel@linux.ibm.com

powerpc/vas: Define and use common vas_window struct

2021-06-20T11:58:56Z

Many elements in vas_struct are used on PowerNV and PowerVM platforms. vas_window is used for both TX and RX windows on PowerNV and for TX windows on PowerVM. So some elements are specific to these platforms. So this patch defines common vas_window and platform specific window structs (pnv_vas_window on PowerNV). Also adds the corresponding changes in PowerNV vas code. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1698c35c158dfe52c6d2166667823d3d4a463353.camel@linux.ibm.com

powerpc/vas: Move update_csb/dump_crb to common book3s platform

2021-06-20T11:58:56Z

If a coprocessor encounters an error translating an address, the VAS will cause an interrupt in the host. The kernel processes the fault by updating CSB. This functionality is same for both powerNV and pseries. So this patch moves these functions to common vas-api.c and the actual functionality is not changed. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/bf8d5b0770fa1ef5cba88c96580caa08d999d3b5.camel@linux.ibm.com

powerpc/vas: Create take/drop pid and mm reference functions

2021-06-20T11:58:56Z

Take pid and mm references when each window opens and drops during close. This functionality is needed for powerNV and pseries. So this patch defines the existing code as functions in common book3s platform vas-api.c Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2fa40df962250a737c804e58202924717b39e381.camel@linux.ibm.com

powerpc/vas: Add platform specific user window operations

2021-06-20T11:58:55Z

PowerNV uses registers to open/close VAS windows, and getting the paste address. Whereas the hypervisor calls are used on PowerVM. This patch adds the platform specific user space window operations and register with the common VAS user space interface. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f85091f4ace67f951ac04d60394d67b21e2f5d3c.camel@linux.ibm.com